import Vue from 'vue'
// v-dialogDrag: 弹窗拖拽属性
Vue.directive('dialogDrag', {
    bind (el, binding, vnode, oldVnode) {
        // 自定义属性，判断是否可拖拽　
        if (!binding.value) return
        const dialogHeaderEl = el.querySelector('.el-dialog__header')
        const dragDom = el.querySelector('.el-dialog')
        dialogHeaderEl.style.cssText += ';cursor:move;'
        dragDom.style.cssText += ';top:0px;'

        // 获取原有属性 ie dom元素.currentStyle 火狐谷歌 window.getComputedStyle(dom元素, null);
        const sty = (function () {
            if (document.body.currentStyle) {
                // 在ie下兼容写法
                return (dom, attr) => dom.currentStyle[attr]
            } else {
                return (dom, attr) => getComputedStyle(dom, false)[attr]
            }
        })()

        dialogHeaderEl.onmousedown = (e) => {
            // 鼠标按下，计算当前元素距离可视区的距离
            const disX = e.clientX - dialogHeaderEl.offsetLeft
            const disY = e.clientY - dialogHeaderEl.offsetTop

            const screenWidth = document.body.clientWidth // body当前宽度
            const screenHeight = document.documentElement.clientHeight // 可见区域高度(应为body高度，可某些环境下无法获取)

            const dragDomWidth = dragDom.offsetWidth // 对话框宽度
            const dragDomheight = dragDom.offsetHeight // 对话框高度

            const minDragDomLeft = dragDom.offsetLeft
            const maxDragDomLeft = screenWidth - dragDom.offsetLeft - dragDomWidth

            const minDragDomTop = dragDom.offsetTop
            const maxDragDomTop = screenHeight - dragDom.offsetTop - dragDomheight

            // 获取到的值带px 正则匹配替换
            let styL = sty(dragDom, 'left')
            // 为兼容ie　
            if (styL === 'auto') styL = '0px'
            let styT = sty(dragDom, 'top')

            console.log(styL)
            // 注意在ie中 第一次获取到的值为组件自带50% 移动之后赋值为px
            if (styL.includes('%')) {
                styL = +document.body.clientWidth * (+styL.replace(/%/g, '') / 100)
                styT = +document.body.clientHeight * (+styT.replace(/%/g, '') / 100)
            } else {
                styL = +styL.replace(/px/g, '')
                styT = +styT.replace(/px/g, '')
            };

            document.onmousemove = function (e) {

                // 通过事件委托，计算移动的距离
                let left = e.clientX - disX
                let top = e.clientY - disY
                // 边界处理
                if (-(left) > minDragDomLeft) {
                    left = -(minDragDomLeft)
                } else if (left > maxDragDomLeft) {
                    left = maxDragDomLeft
                }

                if (-(top) > minDragDomTop) {
                    top = -(minDragDomTop)
                } else if (top > maxDragDomTop) {
                    top = maxDragDomTop
                }

                // 移动当前元素
                dragDom.style.cssText += `;left:${left + styL}px;top:${top + styT}px;`
            }

            document.onmouseup = function (e) {
                document.onmousemove = null
                document.onmouseup = null
            }
            return false
        }
    }
})

Vue.directive('dialogChange', {
    bind (el, binding, vnode, oldVnode) {
        // 自定义属性，判断是否可拉伸
        if (!binding.value) return
        const dragDom = el.querySelector('.el-dialog')
        let dragMouse
        // 在弹出框的右下角添加可拉伸标志 class='dialog-mouse'
        for (let i = 0; i < dragDom.childNodes[2].childNodes.length; i++) {
            if (dragDom.childNodes[2].childNodes[i].className === 'dialog-mouse') {
                dragMouse = dragDom.childNodes[2].childNodes[i]
            }
        }
        // 鼠标拖拽
        dragMouse.onmousedown = (e) => {
            // content区域
            const content = dragDom.parentNode.parentNode.parentNode.parentNode
            const disX = e.clientX - dragDom.offsetWidth
            const disY = e.clientY - dragDom.offsetHeight

            document.onmousemove = function (e) {
                e.preventDefault() // 移动时禁用默认事件
                // 通过事件委托，计算移动的距离
                let width = e.clientX - disX
                let height = e.clientY - disY

                if (width > content.offsetWidth && height < content.offsetHeight) {
                    dragDom.style.height = `${height}px`
                } else if (width < content.offsetWidth && height > content.offsetHeight) {
                    dragDom.style.width = `${width}px`
                } else if (width < content.offsetWidth && height < content.offsetHeight) {
                    dragDom.style.width = `${width}px`
                    dragDom.style.height = `${height}px`
                }
            }
            document.onmouseup = function (e) {
                document.onmousemove = null
                document.onmouseup = null
            }
            return false
        }
    }
})